Automatic telephone-line-finder system.



B. G. DUNHAIVT. AUTOMATIC TELEPHONE LTNE TTNTTETT SYSTEM. APPLICATION FILED MARJI |915.

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AUTOMATIC TELEPHONE LINE FINDER SYSTEM.

APPLICATION FILED MAR. II, 1915. Y v Lmlo. Patented Feb. 27,1917.-

3 SHEETS-SHEET 2.

B. G. DUNHAIVI. AUTOMATIC TELEPHONE LINE FINDER SYSTEM.

Patented Feb. 27, y1917.

B-SHEETS-SHEET 3.

APPLICATION FILED MAR. H, T915.

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UNITED sTATEs PATENT oEEicE.

BERT G. DUNHAM, OF HAWTHORNE, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION 0F NEW YORK.

AUTOMATIC TELEPHONE-LINE-FINDER SYSTEM.

Specification of Letters Patent.

' Patented Feuer, 1917.

Application med Maren 11, 1915. seriai No. 13,625.

To all Iwhom t may concer/n.

Be it known that I, BERT G. DUNIIAH, a citizen of the United States, residing at Hawthorne, in the county of Passaic and State of New Jersey, have invented certain new and useful Improvements in Automatic Telephone-LineFinder Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone testing systems, and is particularly applicable to step-bystep line finders.

Its object generally stated is to enable lines to be tested in succession with accuracy, at high speed and with a minimum equipment for the lines and line finders.

More particularly the invention appertains to the class of selectors known as threewire line finders, that is to say, line finders in which each line is provided, in addition to its two line circuit terminals, with a single local circuit terminal. In such systems, the test for a calling line may be made by two devices or relays, one controlling the opera tive condition of the other, the first testing at the local terminal for the free or occupied state of the local circuit of the line and the second thereupon testing, provided the local circuit is found unoccupied for the closed condition of the line at the subscribers station.

According to this invention, the first test relay is initially actuated preliminary to the joint test by the two relays upon the terminals of each line. This initial actuation occurs intermittently and preferably in step with the movement/of the line finder. Following the initial actuation. the first test relay tests the local circuit of the line, and if it finds this circuit occupied, indicating that there is another connection to that line, it maintains in an inoperative condition the second test relay. If, however, the first test relav finds the local circuit unoccupied, it reacts, placing the second test relay in operative condition, whereupon thel latter relay tests for the closed condition of the line at the subscribers station. If this line is the calling line, the second test relay will be actuated, the line finder stopped and the ldesired circuit for the line extended through the lin'e finder tothe apparatus beyond.

The invention will be more fully understood by reference to the accompanying drawings wherein Figures 1, 2 and 3 together form a diagram of circuits illustrating a line finding system embodying the invention. Fig. 1 includes the `calling line and line finder apparatus; Fig. 2 includes certain auxiliary apparatus and test relays associated with the line finder; and Fig. 3 includes the equipment beyondthe line finder to which the calling line is 'adapted thereby to be connected; Fig. 4 illustrates certain structural features of the side switch, the operating magnets and. contacts of which appear as part of the diagram in Fig. 2.

In Fig. 1 there is shown four subscribers lilies, 1, 2, 3 and 4 of which one only is completed to the subscribers stations 64. rIrlhere is provided for each line an individual cutoff relay 5, 6, 7 and 8 and a line relay 10 which is common to every group of ten lines connected to a line finder switch 11. The line finder 11 may be of any well-known form of step-by-step mechanism having terminal banks 12.13 and 1-1 and corresponding wipers 16, 17 and 18 adaptedto be moved vertically. opposite their respective terminal banks by a magnet 21 and horizontally over the terminals in each level by a magnet 22. A special bank of terminals 15 is provided and adapted to be traversed by a wiper 19 moved in a vertical direction by the magnet 21. A release magnet 23 is provided to release all the wipers to their normal positions.v The line wires 1, 2, 3 and 4 are shown connected to the terminals located in the sixth horizontal level of bank 12, and the wires form the cut-ofi' relays 5, 6, 7 and 8 are connected to the terminals'in the sixth horizontal level of the bank 14. Group wire 24: from the common line relay 10 of this level is connected to the terminal in the seventh level of bank 15. When, therefore, the wipers 16, 17, 18 and 19 have taken six steps vertically, the wipers 16 are located opposite terminals in the sixth level of bank 12, the wipers 17 are located between the fifth and seventh level of bank 13, the wiper 18 is vlocated opposite the sixth level of bank 14 and the wiper 19 is located on the seventh terminal of bank 15. At the subsequent horizontal movement of the wipers, wiper 19 will travel in succession over the terminals in their respective levers.

The side switch structure used in connection with this invention consists of the bank 26 of four groups of three terminals cach and a set 27 of wipers adapted to be released and connect successively with the terminals in the three groups thereof. This is done by the magnet 28 which, for each operation of its armature 29, releases the armature and wiper support 32 one step by means of the escapement springs 30 and 31 attached thereto. This causes the wipers 27 to make successive contact with the three groups of terminals in bank 26. To return the wipers 27 to normal, magnet 34 is energized and attracts the armature 32 which then is locked in its normal position by means of catch 35 by engagement with hooked lever 36. This lever 36 is so shaped that when the magnet 28 is first energized it is raised by the projection 37 and armature 29 to release the armature 32 and is held in this position by means of a portion 38 thereof riding on the top of catch The springs 39 and 40 operated hy the lever 36 are thus held closed during the successive operations of the magnet 28. A pair of springs 41 and 42 are also provided and arranged to open contact every time magnet 28 is operated. The purpose of this construction of the side switch will bel apparent as the description proceeds.

The circuit shown in Figs. 1, 2 and 3 illustrates how a complete connection may be made from the calling subscribe'rs station 64 to the called subscribers station 44, and the operation thereof is as follows:

Then the subscriber at station 64 removes his receiver from the hook the following circuit is closed:

(l) battery, right-hand winding of relay 10, contacts of cut-off relay 6, substation 64, back contact of armature 45, left winding of relay 10 to ground.

Relay. 1.0 is now energized gized by the action of its own armature 45 as long as the receiver remains off the hook. The armature 46 of this relay is so constructed, however. that it will during this period of vibration, pull up at the first energization and maintain the contact 47 closed and contact 48 open, thus during this period providing grounded battery to the starter wire 49 and .keeping it off the group wire 24.

The ground on starter wire 49 establishes the following circuit:

(2) Ground 47, armature 46 and front contact 47 of relay 10, conductor 49, side switch wiper 50, in its first or normal position, conductor 51, wiper 19, conductor 52, left contact of test relay 53,side switch wiper 54 and from there in two directions,

(a) to side switch magnet 28 and battery,

(7)) to contact 70 of rotary magnet 22, contact 68 of vertical magnet 21, and relay 56 to battery.

Part (2a) of this circuit energizes magnet and dener- 28 and its armature opens the contact between the springs 41 and 42 to prevent the release. of the switch during operations hereinafter to be described and prepares the wipers 50, 57, 56 and 54 for subsequent movements to their second position. Part (2b) of this circuit energizes relay 56 and a circuit is closed for the vertical magnet 21 as follows: a

(3) Ground at back contact of armature 60, of relay 61, back contact of armature 62 of relay 63, release Wire 64, wiper 57, first position, contact 65 of relay 56, vertical magnet 21 to battery.

T he vertical magnet being thus energized causes the finder switch wipers 16, 17, 18 and 19 to take one vertical step. The magnet 21 also opens its own back contact 68, thus breaking the circuit for relay 56 which in turn breaks the circuit for the magnet. Therefore, as long as wiper 19 continues to find ground upon the level or group wires such as 24 it will continue to keep magnet 28 and relay 56 supplied with ground and thuscause the vertical magnet 21 to vibrate and advance the wipers until the sixth level is reached where wiper 19 will fail to find grounded battery. The line finder will now stop by reason of the denergization of side switch magnet 28 which causes the set of wipers 27 to advance to their second position. The side switch magnet 28 and relay 56 will then immediately be again energized but over the following circuit:

(4) Ground, 60, 62, 64, wiper 54 second position and circuits (a) and as previously traced.

The vertical magnet 21 is now disconnected from ground at wiper 57 and rotary magnet 22 supplied with battery over the following circuit:

(5) Ground 60, 62, 64, wiper 57, second position, contact 69 of relay 56, rota-ry magnet 22 and battery.

The rotary magnet 22 being thus energized is caused to vibrate by the operation of its own contacts 70.y the same as the vertical magnet- 21 and advances the wipers 16, 17 and 1S over the terminals in the sixth level of their respective banks. rllhe rotary magnet 22 will vibrate and advance the wipers over the terminals as long as the ground on release wire 64 is maintained, that is, until the terminals of the calling` line have been found. The testing for the calling line is done by test relay 53 which is energized and denergized in unison with the rotary magnet 22, over the following circuit:

(6) Ground 60, 62, 64, wiper 57, second position, contact 72 of Arelay 56, test relay 53 to battery.

Therefore, at every denergization of the test relay the wipers 1.6 and 17 are caused to test their respective bank terminals, by

common line relay 10 and being extended by means of line wires 73, 74 through contacts 75, T6 of relay 53 and line wires 7T, 78 to test relay 61. )Vlien the vipers 16 are resting on the terminals leading to a closed line, in this case those of the calling substation 64. relay 61 will be energized over the fo'llowing circuit:

(7) Ground, right winding of test relay 61, 78, 76, 74, one of the wipers 16, through the substation 64, back over the other of the wipers 16. 73, 75, 77, left winding of test relay 61 to battery.

The ground at 6() is therefore taken otll the release wire 64. and relay 66 denergized, thus stopping the line finder with the wipers on these terminals. The magnet 2S was also dene'rgizcd and the side switch wipers 2T thereby released to their third position. Wiper 53 finds a ground at this position and a circuit for cut-ott' relay 8 is established as follows:

(8) Ground, 58, wiper to battery.

The energization of cut-off relay 8 opens the circuit- (1.) for subscribers line 4 to the thus gives a clear extension of the line to relay 61.

vWhenever the line finder advances over the terminals of other busy lines, the relay 53 is held energized and is not allowed to connect the lines 73, 74 for testing of these busy lines. The test relay -Would receive a ground from the side switches of these other busy finders which are then in their third position through their wipers 18 and multiple terminals to the wiper 13 of its own finder and side switch, which is at such a time in its second position. The relay 53 would therefore be held energized while the wipers 16, 17 pass over the terminals of busy lines, but be allowed to denergize and test the calling line when reached.

The circuit shown in F ig. 3 has been arranged so that the subscribers station at 44 can be rung and answered as follows: Test relay 61 being energized by the closed circuit through the calling subscribers line, closes the front. contact of armature 60 to ground and a circuit for slow acting relay 63 is established as follows:

(9) Ground, front contact of armature, 60, relay 63, battery.

In order to ring the called party, it may be supposed that the calling subscriber' interrupts the circuit for relay 61, as for eX- ample, moving his hook up and down a definite number of times, say ten times. The relay 63 being slow acting, will during these linterruptions remain operated and al circuit is closed intermittently for the relay 79 as follows: Y

(10) Ground at 60, 62, relay 79 and bat- 18, cut-ofi relay 8 tery.

Relay 79 which is also slow acting, will pull up at the rst impulse and remain energized during the period of interruptions and establish a. ringing circuit for the called line as follows:

(11) Ground at 80, line 81,'substation 44, line 82 and generator 83.

As soon as the interruptions cease, the test relay 61 will permanently remove the ground from the slow `acting relay 79 and the ringing current will be cut olf, the calling line is now extended for talking purposes through the back contacts ot' relay 79 and the condensers S4 to the called line. Relay 85 is of the usual type of answering relays used in circuits of this kind. No automatic selecting circuit and selecting apparatus has been shown in connection with this circuit to select a line as it is too well known in the art to be here included.

The release of the circuit and thev return of the line tinder'and side switch to normal is as follows: )Vhen the calling subscriber hangs up his receiver, the relay 61 will be denergized and the release wire 64 receiving a ground from 60, the following circuit is established:

(12) Ground 60. 62, 64, 57, contacts 41 and 42, off-normal contact 86, and from there in two directions,

(a) release magnet 23 to battery and (7)) release magnet 34 to battery.

The release magnet 23 beingenergized releases the line finder for its return to normal, and the side switch magnet 34 being also energized, attracts its armature 32 and returns the side switch wipers 27 to their normal position.

To secure the proper release of the line finder to normal position the magnet 23 is maintained energized by the pulling up of its armature 87 as follows:

(13) (-xround at 67, lead 89, 41, 42, magnet 23 to battery.

This circuit will be broken at the off-normal contact 86 as soon as the line finder has returned to normal. In case side switch magnet 34 should for some reason or other fail to respond before the ofi" normal contact 86, that is if the linefinder had returned to normal without the side switch being returned, a contact 93is closed by the 'line finder in normal position and the following circuit established:

(14) Ground, 40, 39, contact 93, magnet 34 to battery.

This circuit will then energize magnet 34 and when the armature 32 is pulled up and locked, the contacts 39 and 40 separate and thus break the circuit (14).

During the return of the line finder to normal, the test' relay 53- is maintained energized over the following circuit to prevent the testing of the terminals by the and the calling subscriber should, for some reason or other, hang up his receiver before his line terminals have been found, the vertical'and rotary magnets Q1, would each in succession advance the wipers to the tenth level and tenth terminal in this level. The wipers 16 when coming in contact with the terminals 90 would iind a closed circuit and thus causing the test relay (3l to operate. This will stop the finder in this position as previously explained; the magnet 28 being denergized advances the side switch contacts 2T to their third position. In this position the side switch wiper 58 is grounded and thus also grounding wiper 18, which is at this vtime resting on the tenth terminal in the tenth level ot' its bank 14. All ot' the tenth terminals in this bank are connected together and lead by means oi wire 9:? to the release magnets 23 and 24 which would in this case be operated and release the line finder and side Switch to normal over the following circuit:

(13) Ground wiper wiper 18, lead 92, 41. l2, SU. magnet 23 to battery and magnet 34 to battery.

'hat is claimed is:

l. In a telephone testing system, lines to be tested in succession, test terminals for said lines, a primary test relay, a secondary test relay operable under the control otl the primary test relay, and means for actuating said primary test relay to disconnect said secondary test relay, preliminary to the test by said relays ot' each line.

2. In a telephone testing system, lines to be testedin succession, test terminals for said lines, primary test relay. a secondary test relay operable under the control ot' the primary test relay, means for actuating said primary test relay to disconnect said secondary test relay preliminary to the test by said relays of each line, and means for keep ing said primary test relay actuated during the testing of the connected lilies.

In a telephone testing system, the combination with lines to be tested in succession,

a line terminal and a local circuit terminal for each line, primary and secondary testing devices for the local and line circuit terminals respectively, the operative condition of said secondary testing device being con` sion, a line. terminal and a local circuit ter' mina] for each line, primary and secondary testing devices for the local and line circuit terminals respectively, the operatvecondition of said secondary testing device being controlled by said primary testing device, means t'or actuating said primary testing device to disconnect said secondary testing device preliminary to the test of each line by said devices, and means cooperating with the local circuit terminals for keeping said secondary testing device disconnected during the testing of connected lines.

In a telephone system, lines, a step-bystep line finder, a stepping magnet therefor, two test relays one to test the idle and the other the calling condition, of lines, means operating intermittently for actuating simultaneously said stepping magnet and one of said test relays, and means controlled by said relays jointly for identifying a calling line.

In a telephone system, lines, means for closing said lines to call or to answer calls, means for interconnecting said lines, and mechanism for testing said lines in succession comprising two relays, one operable during' the testing of connected lines to prevent the other from testing closed lines.

In Witness whereof, I hereunto subscribe my name this 10th day oi March A. D., 1915. 90 

